Mitsubishi STERAPORE 5700 Series Instruction Manual page 26

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Chemical tank (NaClO storage tank)
This is a tank used to store chemicals (NaClO). NaClO is corrosive.
■Design example
Tank capacity: The amount used in 1 to 2 months (calculated including maintenance cleaning and
recovery cleaning)
Tank material: PE, FRP, etc.
Installation location: Indoors, or a shaded, well ventilated location.
■Example of a calculation for the amount of NaClO used in 2 months per 57M0200FF unit
Assume that the concentration of undiluted NaClO solution is 12 % and that its specific gravity is 1.19.
 Maintenance cleaning
2
200 m × 2 L/m
 Recovery cleaning
2
200 m × 2 L/m
The total of the above is 21 L.
Take into account loss equivalent to the guide pipe capacity when choosing a chemical tank.
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Dilution water tank
This is a tank used to store the dilution water for NaClO.
■Design example
Dilution water: Tap water, membrane treated water, etc.
Tank capacity: Must be greater than or equal to the amount required for a single cleaning cycle
Supply method for dilution water: Automatic.
■Example of a calculation for the amount of NaClO used per 57M0200FF unit
× 2 L/m
2
200 m
WAR NI NG
The following are not suitable for use as dilution water.
・Treated water which has a high residual ammonium concentration:
NaClO reacts with ammonium to become chloramine, reducing NaClO activity.
・Water with a high concentration of polyvalent metal ions such as iron and manganese ions:
It reacts with NaClO to precipitate solid content in the membrane.
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Washing tank
This is a tank in which modules are immersed in chemical soak cleaning.
■Design example
Capacity: Large enough and deep enough to accommodate several modules at one time.
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Chemical pump
This is a pump used to deliver NaClO from the chemical tank.
■Design example
Pump type: A variable meter pump. The chemical pump may be shared for maintenance cleaning and
STERAPORE 5700 Series (FF) Instruction Manual
2
× 500 mg/L ÷ 12 % ÷ 1.19 g/cm
2
× 3,000 mg/L ÷ 12 % ÷ 1.19 g/cm
2 3
= 0.4 m (Tank capacity: 0.4 m
3-2-1
Device and Equipment
Design
3
× once/week × 8 weeks/2 months = 12 L
3
× once = 9 L
3
+ guide pipe capacity ⇒ 0.5 m
Chapter 3 Chemical Cleaning
3
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